Syringes are available in a variety of sizes and are intended to dispense (inject) as well aspirate (extract) a variety of substances, most often fluids but also dispersions, gels, solids such as powders, or gases. Syringes are used to inject or aspirate fluid in several therapeutic and diagnostic medical procedures such as the following illustrative examples:                1) Centesis Procedures—including Thoracentesis (removal and optional analysis of fluid in the chest, Paracentesis (removal and optional analysis of fluid in the abdomen), Pericardialcentesis (removal and optional analysis of fluid from the pericardial space around the heart), and Arthrocentesis (removal and optional analysis of fluid from a joint).        2) Abscess Aspiration—removal and optional analysis of fluid collection sites common in the body particularly the breast, brain or kidneys.        3) Contrast Media Injection—special fluid to better visualize blood vessels for cardiology procedures. Aspiration is used to verify the needle puncture into a vasculature, and injection is used to deliver the contrast media into the vasculature.        4) Exchange Transfusions—including slow and careful replacement of blood for adult and pediatric blood diseases.        5) Surgical Wound Irrigation—including high velocity cleansing of traumatic injuries. A syringe aspirates saline, for example, from a reservoir and irrigates a wound site.        
The nature of these procedures typically involves extensive manipulation of the syringe and stabilization of the injection/aspiration site. These tasks are more difficult with high viscosity fluids and/or larger syringes.
Syringes can be manually operated with one or two hands, can be manually operated with the assistance of a holding/actuation accessory, or can be used with a variety of automatic devices which aide in controlling the movement of the substance within the syringe. Automation comes with additional cost, size, and maintenance disadvantages compared to manual activation.
Larger size syringes, such as 60 mL ones, are common and well-suited for many procedures. However, larger sized syringes are more challenging to use manually with one hand, even when used in combination with conventional actuation accessories. This difficulty could compromise patient safety, delivery and aspiration accuracy, and/or extend procedure times. Having a second person assist in helping resolve these issues increases procedure cost.
Syringe accessories in the form of hand pieces or devices have been described and developed that address some of the challenges associated with using syringes to accomplish aspiration. A handheld device used with syringes to provide aspiration function is depicted in patents such as U.S. Pat. No. 5,469,860 and USD337821. A commercially available device is available from Inrad, Inc. (Kentwood, Mich.) under the trade designation Aspiration Biopsy Syringe Gun. Several devices also have been described that are used with syringes to dispense syringe contents. See, e.g., USD576273.
Some syringes include features to assist with single handed aspiration. These features include loops or rings to facilitate finger and thumb action. These features can facilitate both dispensing and aspiration. Several variations of an early control syringe exist. See, e.g., U.S. Pat. No. 4,516,969.
Commercially available devices with trigger-actuated ratchet mechanisms are used in so-called caulk guns for dispensing adhesives and caulking materials from prefilled cartridges. The guns and cartridges are available in different sizes. Illustrative products are and manufactured by companies such as 3M Co. (St. Paul, Minn.) and Henkel Corp. (Rocky Hill, Conn.). A recent patent US7757904B2 is an example of such a device for caulk cartridges.
Commercially available bar clamping devices exist that utilize ratchet mechanism principles. Examples are US8074340B2 and U.S. Pat. No. 4,926,722. Some of these clamps can be reconfigured to a spreading bar clamp as described in U.S. Pat. No. 5,009,134. These devices illustrate how high forces can be used to create a clamping or spreading motion. A bar clamp that uses a switching mechanism to select between clamping and spreading functions is described in US7325797B2. A third example device is marketed by Avanca Medical Devices, Inc and described in US7967793B2. This device allows the dispensing and aspiration of a syringe with a single hand. A fourth example is a balloon inflation device that utilizes a threaded plunger that is rotated clockwise or counterclockwise to advance or retract the plunger of a syringe. See, e.g., U.S. Pat. No. 5,057,078.
There are other applications where it is desired to have an ability to control motion of one or more components and the direction of such motion. Some additional applications involve controlling the motion of a fluid (e.g., to dispense, inject, or aspirate a fluid). Other applications involve controlling the position of one or more solid items.
Many conventional designs can limit or impede a user from dispensing and aspirating syringes, particularly large sized ones with one hand when one hand operation is desired. Therefore, in light of these challenges, it is desired to have a compact and lightweight device that can provide easy dispensing and aspirating modes when used with a syringe, the ability to switch between the two modes and do all this with one hand if desired without requiring outside assistance or requiring setting the syringe down at any point. It is also desirable that the device be able to provide mechanical advantage so that the user-applied force can be leveraged for very high dispensing or aspiration forces. It also is desired that the device be MRI safe and compatible, since therapeutic and diagnostic procedures using syringes may be conducted under Magnetic Resonance Imaging (MRI).